Full Idea
Belief is nothing but a more vivid, lively, forcible, firm, steady conception of an object, than what the imagination alone is ever able to attain.
Gist of Idea
Belief is stronger, clearer and steadier than imagination
Source
David Hume (Enquiry Conc Human Understanding [1748], V.II.40)
Book Reference
Hume,David: 'Enquiries Conc. Human Understanding, Morals', ed/tr. Selby-Bigge/Nidditch [OUP 1975], p.49